A new library opened last month in Norway. But it may be a little hard for you to visit. It is 150 meters under the ground. It is inside an old mine(矿井) on the island of Svalbard. The island is about 1,000 km from the North Pole(北极).
The library is called The World Arctic Archive. In fact, it's not made for people to visit. It is to protect the world's most important books from natural disasters(自然灾害) and wars，reported the Daily Mail. Some people also call it the "doomsday(世界末日)library".
According to the company that built the library, Svalbard was the best place to build it. "Deep in the permafrost(永冻土层), it's about minus 10 degrees," the company told The Verge. "In this environment, the books can last for more than 500 years."
So far, three countries-Norway, Mexico and Brazil have put books in the library. The Brazilian Constitution(宪法) is one of the books.
